Roto-piston engine



3, 1968 w. J. RBICHEAUX 3,396,709

ROTO-PISTON ENGINE Filed May 9. 1966 6 Sheets-Sheet 1 13, 1968 w. J.ROBICHEAU* 3,396,709

ROTO-PISTON ENGINE Filed May 9, 1966 6 Sheets-Sheet 2 INVENTR. W4AENJOBIC/'AUX Aug. 13, 1968 w. J. ROBICHEAUX ROTO-PISTON ENGINE 6Sheets-Sheet 3 Filed May 9. 1966 Aug. 13, 1968 w. J. ROBICHEAUXROTO-PISTON ENGINE 6 Sheets-She6t 4 Filed May 9, 1966 Aug. 13, 1968 w.J. ROBI'CHEAUX ROTO-PI STON ENGINE 6 Sheets-Sheet 5 Filed May 9. 1966 g-1968 W!J. ROBICHEAUX 3,

ROTO-PISTON ENGINE Filed May 9. 1966 6 Sheets-Sheet 6 F.zg. 10

Unted States Patent O 3,396,709 ROT-PISTON ENGINE Warren J. Robicheaux,Port Arthur, Tex., assrgnor t o Gulf Oil Corporation, Pittsburgh, Pa., acorporatron of Pennsylvania Filed May 9, 1966, Ser. No. 548,570 9Claims. (Cl. 123-45) ABSTRACT OF THE DISCLOSURE A number of dilerentengines, both four-cycle and two-cycle, which utilize a unitary doubleopposed pistons and cam wheel member are described. Means are providedto hold the edge of the cam wheel at two locations in the housing. Theexplosion of the fuel mixture against the face of one piston moves theassociated member axially. The axial motion is simultaneously convertedinto rotation of the entire member by interaction of the rollers at theedges of the cam wheel.

This invention relates to a rote-piston cam engine, wherein the basicmoving part is a piston-cam member comprising a geared cam wheel havinga piston fixed to each of the opposing sides thereof, and which directlyconverts the reciprocatory translational motion of the member t0rotational movement.

The piston-cam member allows more freedom in varying stroke t0 pistonratios, and produces engines with more horsepower per cubic inchdisplacement or pound of weight than conventional reciprocating pistonengines. An overhead valve cam shaft is also provided for better valveaction.

The engine can be operated as either a twocycle or a four-cycle engine,and when operated as a two-cycle engine, the piston opposite the powerpiston can act as a compresser supercharger.

In a conventional four-cycle reciprocating piston engine, each pistonfires once for every two complete turns of the crank shaft. In thefour-cycle engine of the present invention, each piston fires once foronly one complete turn of the piston-cam member.

In an alternative embodiment of the invention, two additional piston-cammembers are provided, making a total of four such members, and therebyproviding an engine comparable to a conventional eight cylinder engine.This embodiment provides an even greater advantage in its horsepower orcubic displacement to weight ratio. Virtually any number of pistons,including one, could be provided. By changing the configuration of thegeared cam wheel, more or less firings per revolution of the piston-cammember is possible.

In the accompanying drawings forming a part of this disclosure;

FIG. 1 is an end elevati0nal view of a first embodiment of an enginehaving four cylinders embodying the invention;

FIG. 2 is a top plane view thereof with the valves and valve liftingmechanisms omitted;

FIG. 3 is a crosssectional view taken on line IIIIII on FIG. 1;

FIG. 4 is a cross-sectional view taken on line IVIV of FIG. 3;

FIG. 5 is a prospective view of one piston;

FIG. 6 is a view similar to FIG. 1 illustrating a modified form of theinvention;

FIG. 7 is a view similar to FIG. 1 illustrating another modified form ofthe invention;

FIG. 8 is a cross-sectional view through a drive shaft illustrating amodified form of the valve lifters, showing them set-up for four-cycleoperation.

3,396,709 Patented Aug. 13, 1968 FIG. 9 is a partial-sectional viewtaken at right angles to FIG. 8, similar to one side of FIG. 3, andshowing the modified cam lifter structure set-up for two-cycleoperation; and

FIG. 10 is a view similar to FIG. 3 illustrating still another modifiedform of the invention.

Referring now in detail to the drawings, 10 designates a four cylinderfour-cycle internal combustion engine embodying the invention. Engine 10comprises a pair of end manifold plates 12 each carrying an intakemanifold 14 and an exhaust manifold 16. The manifolds may be secured tomanifold plates 12 by any suitable means. A valve lifter cover plate 18is secured to the manifolds 14 and 16 by any suitable means.

Each manifold plate 12 is provided with a plurality of internalinterconnected cavities 20 which are connected to a conventional coolingwater system not shown. Manifold plate .12 is formed with intake ports22 and exhaust ports 24 which communicate with the intake and exhaustmanifolds 14 and 16, respectively. The innermost wall of each port 22,24 is disposed at an angle to the direction of piston reciprocafion, aswill appear more clearly below. Wall 22 is formed with a valve seat 23and wall 24 is formed with a valve seat 25. Plate 12 is provided withwalls 26, which each form substantially a right angle with each wallcarrying a valve seat, to thereby form a combustion chamber in front ofeach piston, as is well known to those skilled in this art. Removablysecured in a suitable opening in wall 26 is a conventional spark plug28.

As is well understod in this art, an electrical system is provided, butis not shown for the sake of clarity. Similarly, carburetion, exhaust,and lubricating systems, and other auxiliaries are provided but are notshown.

Rotatably mounted in plate 12 are a pair of valve lifter shafts 30, eachof which carries a pair of Valve lifter cams 32. Valves 34 each comprisea valve head 36 cooperable with valve seats 23 and 25 respectively, avalve stem 38 slidably mounted in a convenient portion of valve plate12, a spring retainer plate 40 fixed to valve stem 38, and a valve stemtip 42 cooperable with the lifter cams 32. A spring 44 is mountedbetween plate 40 and manifold plate 12, and is arranged t0 normally urgeeach valve head 36 into seating engagement with its respective valveseat. Fixed to each Valve lifter shaft 30, between the cams 32, is ahelical gear 46. Each pair of helical gears 46 are driven by a helicalgear 48 mounted on main drive shaft 50.

Joined to the inside surface of each manifold plate 12 is a cylinderhousing member 52. A suitable gasket 54 is interposed between member 52and plate 12 which are joined together by conventional bolts 56 in theconventional manner to create a predetermined combustion chamber volume.Member 52 is formed with a plurality of interconnected cavities 58 whichare also connected to cavities 20 and the cooling system for the engine.A main shaft bearing 59 is mounted in both plate 12 and member 52, andbridges the plane of their juncture. Each cylinder housing 52 is formedwith a pair of cylinders 60.

Mounted on the inside surface of each member 52 is an inner cover member62. Members 62 are in spaced relation to each other, but areinterconnected by a continuous housing cover 64, and are. each securedthereto by means of bolts 66. Al] joints between inner cover members 62and the members 52 and cover 64, as well as similar joints in theembodiments described below, are suitably gasketed by means not shownfor the sake of clarity. Each member 62 is joined to its respectivemember 52 by a plurality of bolts 68. Member 62 is formed with anopening 70 in registry with cylinder 60. Each member 62 carries a mainshaft bearing 72 in registry with the bearings 59. Shaft 52 carries apair of iy-wheels 74, each of Which runs in a cavity 75 formed in eachmember 52 between the cylinders 60. Fly-wheels 74 may be omitted incertain size engines if desired, since the geared cam wheel may be heavyenough to also function as a fiy-wheel.

Mounted in each cover member 62, with one on each side of each cylinder60, are four piston-cam plate supporting rollers 76. The rollers 76 ofeach cover member 62 are in facing relation to the rollers of the othercover member, thereby forming four pairs of rollers. Each two pairs ofrollers 76 on each side of main shaft 50 are in equidistantly spacedrelation to the center line of the facing pair of cylinders 60 in thetwo members 52 on that side of the main shaft.

Rotatably mounted by each such adjacent two pairs of rollers 76 is arigid piston-cam member 78, each comprising a geared cam wheel 80. Theplane of cam wheel 80 is disposed generally perpendicular to the axis ofthe two adjacent cylinders 60, but the wheel undulates peripherally inthis axial direction, and is provided with a first pair of opposed highpoints offset by 90 from a second pair of opposed high points, each twoadjacent high points being interconnected 'by a smooth fiowing curve.The pe- -ripheral edge of wheel 80 is provided with gear teeth 82. Theside peripheral portions of cam wheel 80 is rotatably receved and heldbetween the rollers 76, and the peripheral thickness of said cam wheelvaries slightly around its circumference to achieve a smooth and uniformmotion of the pistons, as will appear more clearly below. A piston shaft84 extends through and is joined to the center of cam wheel 80.Thickened portions 86 are provided to rigidify and strengthen the jointbetween shaft 84 and wheel 80. Of course, these portions could be castor forged or otherwise fabricated in one piece, if desired. A piston 88is fixed to each end of shaft 86 and is slidably and rotatably receivedin cylinder 60.

Referring to FIG. 5, piston 88 comprises a plurality of sealing rings90. The face 89 of the piston slopes outwardly and rearwardly and isprovided with a plurality of forwardly extending fins 92. The frontsurfaces 93 of fins 92 are in a plane perpendicular to the axis of thepiston. Since the pistons 88 rotate Within as vvell as slide Withincylinders 60, fins 92 create a greater turbulence Within the cylinderspace during both intake of a charge and scavenging after firing. As iswe known in this art, increased turbulence Within the combustion chamberis a greatly desirable advantage since such turbulence aids fueldistribution Within the chamber, lowers fuel consumption, increasesefliciency and increases engine power.

Fixed to main shaft 50, between bushings 72, is a gear 94 which mesheswith the gear teeth 82 on the two cam wheels 80.

The engine of the present invention can be made in a large range ofsizes to almost any power requirements. The dimensional relationshipsWithin the drive train can also be varied as required. However, for thesake of example, in the engine shown, the diameter of each cam wheel 80is about twice that of gear 94. Cam wheel 80 will move each piston 88through one stroke in a quarter revolution since it will move from thehigh point of one pair of high points to the high point of the adjacentpair of high points in 90. Therefore one complete four-cycle stroke,that is, intake-compression-power exhaust, of each piston will requireone revolution of each cam wheel 80, and since each cam wheel carriestwo pistons, there will be a firing every 180 of rotation of the camwheel. Because of the dimensional relationship mentioned above, eachcomplete four-cycle stroke will therefore cause one complete revolutionof :gear 94 and hence main drive shaft 50. Since each cylinder 60 hasboth an intake valve and an exhaust valve associated with it, and eachvalve must open and close once per complete four-cycle stroke of eachpiston, helical gears 48 and 46 are in a 1 to 2 diametric relationship.

The four-cycle internal combustion cycle is well known, but for the sakeof illustration will be briefly explained as follows.

Referring to FIG. 3, the four cylinders are labeled A, B, C, and D forthe sake of discussion. Starting from the position shown in FIG. 3 andassuming the engine is in continuons operation, cylinder A is about tobegin exhausting a spent charge, cylinder B has just been fired,cylinder C has just completed an intake stroke and cylinder D has justcompleted an exhaust stroke. 90 of rotation of cam wheels later, in thedirection of the arrows in FIG. 3, cylinder A will be completing anexhaust stroke, cylinder B will be completing its power stroke, cylinderC has finished a compression stroke and will be firing, and cylinder Dwill be completing its intake stroke. Another et rotation et the camwheels 80 later, in the direction of the arrows in FIG. 3, cylinder Awill be completing an intake stroke, cylinder B will be completing anexhaust stroke, cylinder C will be completing a power stroke, andcylinder D will be firing.

Thus, each power stroke causes 90 of rotation of the associated camwheel 80 and therefore 180 of rotation of the drive shaft 50. T he poweris transmitted to the gear 94 since the power of the exploding chargeagainst the pis ton pushes the geared cam wheel against the two rollerbearings on the side of the cam wheel opposite that piston. Since thecam wheel is smoothly sloped all along its periphery, it will rollagainst said pair of rollers 76, rotate about its axis, and thereby turngear 94 180 for each power stroke. Thus, the reciprocatory translationlmotion of the piston-cam member is converted directly into rotationalmotion, and the power is transmitted via the rotational motion to thedrive shaft 50.

Referring to FIG. 6 there is shown an engine 10a which is similar toengine 10 of FIGS. 1 to 5, but modified for two-cycle operation. In thefour-cycle engine described above each piston fires once for eachcomplete turn of its associated cam wheel. The basic change in theembodiment of FIG. 6 is that one piston of each pair is converted to asupercharger or compresser for the other piston of that pair, andtherefore the power piston of each pair fires twice for each revolutionof its associated geared cam wheel since the suction stroke iseliminated. Of course, the timing of the valves is appropriatelyadjusted.

In place of the intake and exhaust manifolds 14 and 16, thesupercha1ging cylinder 96 is provided with an intake manifold 98 and anexhaust manifold 100. Exhaust manifold 100 empties into a reservoir orcompression bottle 102. The outlet end of bottle 102 is connected to anintake manifold 104 for the power cylinder 106. Cylinder 106 is providedwith an exhaust manifold 108. The intake and exhaust valves forcylinders 96 and 106 are not shown, but are similar to these shown inFIG. 3. It will also be understood that the pair of cylinders associatedwith the piston-cam member on the other side of the engine has a similarmanifold and compression bottle arrangement.

Assuming the engine of FIG. 6 is running continuously and the powercylinder 106 has just fired, the next 90 et rotation of the associatedcam wheel will cause compression of a charge in cylinder 96 during thatpower stroke in cylinder 106. At the end of this first 90 of rotation,intake manifold 98 will be closed, the compressed but unfired charge incylinder 96 will be released into the compression bottle 102 and theexhaust valve leading to exhaust manifold 108 for cylinder 106 will beopened. During the next 90 of rotation of this cam wheel, a fresh chargewill be drawn into cylinder 96, and cylinder 106 will simultaneouslyexhaust the spent charge and take in a fresh already compressed chargefrom bottle 102. At the end of this second 90 of rotation the powercylinder 106 will be ready to fire again and the cycle will repeat.Within the cycle, the exhaust valve closes at the beginning of thecompression stroke. The intake valve is opened just prior to the closingof the exhaust valve. The intake valve stays open for about 15 degreesof turn of the cam-wheel, which is long enough to equalize the pressurein bottle 102 and cylinder 106. T he piston then continues forward andfurther compresses the fresh charge. This arrangement allows for morecharge volume under higher pressure With a lower compression ratio.

The engine of the present invention is very versatile. The piston strokecan be lengthened or shortened by changing the amplitude, that is, thedistance from high point to high point, in the axial direction, on thegeared cam wheel. The number of power strokes per revolution of thegeared cam wheel can be changed by changing the undulations or number ofcycles of curvature, that is, the number of high points on the gearedcam wheel. R.p.m. can be changed by adjusting the gear ratio between thegeared cam wheels and the main shaft gear, with appropriate adjustmentsfor the valve lifters. Any number of cylinders, including one, can beprovided, within the practical limitations of locating the associatedgearing.

In FIG. 7 is shown an eight cylinder angine 1% which comprises fourpiston-cam members 78b showing the manifolding for four-cycle operation.Said manifolding comprises an intake manifold l4b suitably branched tofeed each of the four cylinders at the end of the engine shown, and anexhaust manifold 16b similarly branched. The geared cam wheels 80b drivea main shaft gear 9%. The engine of FIG. 7 will greatly increase thehorsepower per cubic inch of displacement, and horsepower per pound ofWeight ratios, and would not excessively increase the space required forthe engine. Engine 1% could be set up for two-cycle operaton by makingchanges similar to those described above for converting engine to engine10a. It will be understood that those portions of the engine 1017 notshown in full detail in FIG. 7 are the same as the analogous portionsdescribed above, With obvious changes in the housing members, auxiliarysystems, and the like to accommodate the two additional piston-cammembers and the four additional cylinders.

While engine 1017 can be considered the equivalent of a conventionaleight cylinder angine in that both have eight cylinders, the two enginesare not otherwse comparable, in that in engine 10b there will be eightpower strokes per revolution of the :geared cam wheel whereas in theconventional eight cylinder engine there are only four power strokes parrevolution of the crankshaft.

Referring to FIG. 8, there is shown a modified valve lifter assembly 108which replaces helical gears 46 and 48, valve lifter shaft 30, and cams32. This alternative form of valve lifter -mechanism is functionally thesame as the valve lifter mechanism of FIG. 3. Assembly 108 comprisesfour rings, 110, 112, 114, and 116. Each ring comprises a raised camportion 111, 113, 115, and 117 respectively. The rings are fixed to themain drive shaft 50c by keys 118, or by any other suitable means. Theouter peripheral face of each ring slopes inwardly, and the largestdiameter of any one ring is Substantially equal to or less than thesmallest diameter of the next preceding ring, whereby the four rings incombination describe the shape of a truncated cone in cross-section. Thevalve stems 38c in FIG. 8, or 38d in FIG. 9, have their respectiveworking tips riding on one of the four rings. The angle of dispositionof the peripheral surface of each ring is such that the axis of thevalve stem will be substantially perpendicular thereto, so that the camportions will move the valve stem the full height of the cam portion. Itwill, of course, be understoodthat the valve stems are suitablysupported and spring loaded to the closed position in the manner shownin FIG. 3, or in any other suitable manner. The valve lifter assembly108d et FIG. 9 is suitable for use With the two-cycle engine shown inFIG. 6, and the valve lifter assembly 108 of FIG. 8 is suitable for useWith the engine of FIGS. 1 to 5, the difference hein-g, as is obvious,in the number of valves required, the timing of the valves, and hencethe disposition et the cam portions on the respective rings.

In FIG. 10 there is shown a two-cycle valveless engine embodying theinvention. Engine 120 includes four cylinder bodies A, B, C, and D. Thecylinders are mounted on a pair of cylinder cover members 122, which areinterconnected by a housing cover 124 and secured with bolts 126. Eachcylinder cover 122 carries four cam wheel supporting rollers 128arranged in facing relation across the space between the cover members,to provide four pairs of rollers, With two pairs on each side. of themain Shaft 130. Shaft 130 is supported centrally of members 122 by meansof bearings 131. The two pairs of rollers 123 on each side of the mainshaft are arranged in equidistantly spaced relation from the center lineof the piston-cam member 132 for the two cylinders on that side.Similarly to the embodiments described above, each member 132 comprisesa -geared cam wheel 134 provided With gear teeth 136 on its peripheraledge, which gear teeth mesh with a main gear 133 on shaft 130. A pistonshaft 138 is fixed to and passes through the center of the cam wheel134, and a piston 140 is fixed to each end of said shaf.t, and isslidably and rotatably received within the cylinders A and D in the onecase, and cylinders B and C in the case of the second pistoncam member.The pistons 140 may be the same as pistons 88 of FIG. 5.

Each cylinder A, B, C and D comprises a cylinder body 142 having anenlarged inner cylinder portion 144 suitably flanged as at 146 forsecuring to the cover 122 by means of bolts 148. A sealing member 147,carrying sealing means 149 to permit passage of the main Shaft, protectsthe main shaft bearings 131 and may also seal this area for lubricationpurposes. Member 147 is also held in place by bolts 148. The inner endof each cylinder is sealed by a suitable baflle 150 interposed betweenflange 146 and the cover, and also held by bolts 148. Sealing means 152are provided in baflle 150 to rotatably and slidably receive pistonshaft 138. Forwardly of inner cylinder portion 144 is an outer cylinderportion 154 provided with air cooling fins 156. The inside diameter ofouter cylinder portion 154 is smaller than the inside diameter of innercylinder portion 144 for a reason which will appear below. The outer endof each cylinder is closed off by a cylinder head or cover 158 which isheld to the outer cylinder portion 154 by means of bolts 160. Cylindercover 158 carries a spark plug 162, and the inner face of said cover isin a predetermined spaced relation to the working face of piston 140when the piston is at the outer end of its travel to provide acombustion chamber therebetween, as is well known in the art.

Each cylinder is provided with an intake manifold 164 connected to anintake port 166 formed in inner cylinder portion 144. Outer cylinderportion 154 is formed with an exhaust port 168 mediately the endsthereof. An internal communicating port 170 joins the external end ofinner cylinder portion 144 With outer cylinder portion 154. Port 170 isaxially closely spaced to but axially rearwardly of exhaust port 168,for a reason which will appear below.

The cylinder firing sequence is A, B, D, C. In the position shown inFIG. 10, cylinder A is firing, and cylinder D is just completingscavenging a spent charge and is about to close port 170 to begin acompression stroke. Closing of port 170 creates a vacuum in the innercylinder portion 144 of cylinder D, which vacuum will draw a freshcharge into said portion through its intake port 166. The piston incylinder B is approaching the end of its compression stroke and willfire next. The piston in cylinder C is moving to the right in FIG. 10,and will first uncover its exhaust port 168 and shortly thereafreruncover its communicating port 170 to admit a new charge which has beenslightly compressed in the process in its inner cylinder portion. As isconventional in two-cycle engines, the inlet to inner cylinder portion144 is provided with check valve or other suitable means to insure thisslight compression et the new charge before it is admitted to outercylinder portion 154. This 7 compressed charge entering the outercylinder portion through the communicating port simultaneously chargesthe cylinder and aids in scavenging the spent charge.

Each cylinder fires once per half turn of its associated geared camwheel.

As in the tour-cycle engine described above, efficiency over priorinterna] combustion engines will be gained because of the reduction offriction, since there is basically only one moving part, the piston-cammember, which also reduces the work load per power stroke.

In engine 120 as well as in the engines of a.ll the other embodiments, apower stroke has to overcome the friction of only one additional piston,whereas in more conventional internal combustion angines each powerstroke has to overcome the friction of three, five or seven additionalpistons and their crank mechanisms. In the present invention, such crankmechanisms have been eliminated, since the piston-cam member couvertsthe reciprocation of the pistons directly into rotation.

While the invention has been disclosed in detail above, it will beunderstood that the embodiments shown are for purposes of illustrationonly, and the protection granted is to be limited only .by the spirit ofthe invention and the scope of the following claims.

I claim:

1. A four-cycle engine comprising a housing formed wvith a pair ofopposed, symmetrically disposed cylinders interconnected at their innerends by a central housing portion, a unitary double piston and guidingplate member consisting of a pair of piston members and a guiding plateportion with one piston member in each of said cylinders and With saidguiding plate portion in said central housing portion, said pistonmembers defining a pair of combustion spaces between their outer endsand said housing, respectively, and a central unrestriced space 13etweentheir inner ends, said central unrestricted space being further definedby portions of said cylinders and said central housing portion, saidhousing cmprising means cooperable With the outer faces of said pistonmembers to urge said unitary member into reciprocatory axial motionwithin said opposed cylinders, means to convert the forces imparted tosaid (faces of said piston members t0 forces which rotate said unitarymember about the axis of said unitary member and which permitsimultaneous axial mofi-on thereof; said conversion means consisting ofa plurality et guide rollers in said central housing portion cooperablewith a smooth, continuons, undulating, peripheral portion of saidguiding plate portion on both sides of said guiding plate portion and onopposite sides of the axis of said unitary member; said guide rollersdefining planes disposed substantially perpendicular to the axis of saidunitary member, the regions of engagement :between said guide rollersand said gtfiding plate portion being contained in said perpendicularplanes and said peripheral portion being embraced between pairs et guiderollers of said plurality of guide rollers, and said guiding lateportion being substantially contained in planes parallel to saidperpendicular planes.

2. The combination of claim 1, and power transmission means in saidhousing, said power transmission means being located in planesperpendicular to the axis of said unitary member, and said guiding plateportion comprising means cooperable with said power transmission means.

3. The combination of claim 2, said housing comprising a shaft rotatablymounted therein, said power transmission means comprising a gear fixedto said shaft, and said cooperable means in said guiding plate portioncomprising gear teeth in mesh with said gear.

4. The combination of claim 1, the distance in the axial directionbetween each two adjacent undulations of said guiding plate portionbeing substantially equal to the stroke of each piston member in itscylinder.

5. The combination of claim 1, and fin means on the face of each pistonmember opposite said guiding plate portion, said fin means extendingaxially outwardly of said face.

6. The combination of claim 1, the axial length of said unitary memberbetween the outer faces of the two piston members being less than theinternal axial distance between the outer ends of said two cylinders byan amonnt substantiafly equal to the stroke of one of said pistonmembers.

7. The combmation of claim 4, a second unitary member in said housing,means forming third and fourth cylinders in said housing, the two pistonmembers of said second unitary member .being axially and rotaablymovable in said third and fourth cylinders respectively; and the axes ofsaid two unitary members and said shaft being parallel.

8. The com bination of claim 3, the axis of said unitary member and theaxis of said shaft being disposed in parallel relation, intake valvemeans and exhaust valve means for each of said cylinders, each of saidvalve means comprising a valve stem, a valve lifter cam shaft in saidhousing disposed perpendicular to the axis of said unitary member andsaid first mentioned shaft, valve lifter oams on said cam shaft inoperative engagement With the ends cf said valve stems, and transfermeans on said cam shaft and said first mentioned shaft to drive said camshaft.

9. The combinaton or claim 3, the axis of said unitary member and theaxis of said shaft being disposed in parallel relation, intake valvemeans and exharu3t valve means for each of said cylinders, each of saidvalve means comprising a valve stem, a valve lifter cam ring on saidshaft for each of said valve stems, the tip of each valve stem being inoperative engagement with its respective cam ring, and the largestdiameter of each ring being adjacent to and substantially equal to thesmallest diameter of an adjacent ring.

References Cited UNITED STATES PATENTS 1,813,259 7/1931 Schick 7456 X2,473,936 6/1949 Burf0ugh 12345 1,127,267 2/1915 McElwain 123582,083,510 6/1937 Stig6Is 123-58 2,269,281 1/ 1942 MicheIl 123-582,352,396 6/1944 Maltby 123-45 X 2,983,264 5/1961 Herr-mann 123-58WENDELL E. BURNS, Primary Examiner.

